There are many applications within the aircraft industry and other industries where fasteners are installed into prepared openings or holes in a workpiece or workpieces using a specialized installation tool. Examples of such fasteners include lockbolts, rivets, rivetless nut plates, blind bolts, and blind rivets. Installation tools for these types of fasteners generally include an air, air-hydraulic, or other pulling mechanism that is connected to a draw bolt inside a particular pulling head that is specialized for a selected type of fastener. The installation tools and pulling heads include members that act under compression to force the pulling head against the workpiece into which the fastener is to be installed and other members, including a mechanism for gripping the fastener, that act under tension to install or up-set the fastener in the hole of the workpiece or workpieces. To facilitate use of the installation tool with different types of fasteners, the pulling head may be removable from the installation tool and interchangeable with other pulling heads.
Many situations arise, particularly during maintenance of already-built aircraft and other structures, where fasteners must be installed at locations that are not accessible with typical installation tools because the tool itself cannot fit into the space adjacent to the fastener location. Extension devices are available that fit between the installation tools and the pulling heads. Because the relatively large pulling forces and compressive forces required for fastener installation must be transmitted through the extension devices, the extension devices used to date are rigid and allow force transmission in a straight line between the installation tool and the pulling head. However, situations arise where the fastener is to be installed in a location where the installation tool equipped with a rigid extension device and pulling head does not allow proper alignment of the installation tool with the workpiece into which the fastener is to be installed.
Thus, there is a need for a flexible extension that can be inserted between an installation tool and a pulling head, yet provides for transmission of both tensile and compressive forces when the installation tool and the pulling head are in an offset alignment relative to each other.